build: remove buildflags workaround (#27372)

.circleci/config.yml

@@ -447,10 +447,6 @@ step-fix-sync-on-mac: &step-fix-sync-on-mac
         # Fix Clang Install (wrong binary)
         rm -rf src/third_party/llvm-build
         python src/tools/clang/scripts/update.py
-        # Temporarily use an older version of gn
-        unset CI
-        python src/buildtools/ensure_gn_version.py git_revision:53d92014bf94c3893886470a1c7c1289f8818db0
-        export CI=true
       fi
 
 step-install-signing-cert-on-mac: &step-install-signing-cert-on-mac

BUILD.gn

@@ -3,6 +3,7 @@ import("//build/config/ui.gni")
 import("//build/config/win/manifest.gni")
 import("//components/spellcheck/spellcheck_build_features.gni")
 import("//content/public/app/mac_helpers.gni")
+import("//electron/buildflags/buildflags.gni")
 import("//extensions/buildflags/buildflags.gni")
 import("//pdf/features.gni")
 import("//ppapi/buildflags/buildflags.gni")
@@ -20,7 +21,6 @@ import("build/npm.gni")
 import("build/templated_file.gni")
 import("build/tsc.gni")
 import("build/webpack/webpack.gni")
-import("buildflags/buildflags.gni")
 import("electron_paks.gni")
 import("filenames.auto.gni")
 import("filenames.gni")